Problem with Featured Image Thumbnail

As I posted a featured image for my post, it appeared fine on my featured slide but for some reason, this image is not appearing on my post thumbnail, rather there is another image there that I haven’t selected??? Help!
You can see on the slider that the post called: 5 Things Tuesday… Turn your “Cheat Foods” into “Fit Foods” has the proper featured image, when you scroll down to see this same article it has selected some other image that has nothing to do with the post.
http://myfitstation.com/